Method for manufacturing roofing products

ABSTRACT

A method of making a roofing product such as a shingle is provided. One such method includes creating a mixture having at least a polymer and a filler, forming a sheet from the mixture, cooling the sheet, embossing the sheet, forming multiple roofing products from the sheet and bundling at least some of the roofing products together. This method is performed using an automated procedure. Another method of the present invention involves creating a composite roofing product using mold cavities, using a robot to transfer some of the roofing products from some of the mold cavities to a conveying system, and stacking together at least two of the roofing products that have different colors of different surface configurations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a divisional of and claims priority to U.S.application Ser. No. 10/457,728 filed Jun. 9, 2003 entitled “Method forManufacturing Roofing Products,” currently pending, which is acontinuation-in-part of U.S. Pat. No. 6,935,089 issued Aug. 30, 2005,which documents are hereby incorporated by reference to the extentpermitted by law.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

None.

BACKGROUND OF THE INVENTION

The present invention relates to a method of manufacturing roofingproducts. In particular, the invention relates to an automatedmanufacturing process for producing shingles.

Traditional roofing products such as asphalt shingles, wood shakeshingles, slate shingles and metal panels have both benefits anddetriments. For instance, wood shake and slate roofs are aestheticallypleasing to many homeowners. However, wood shake shingles are considereda fire hazard while slate shingles are very expensive and subject tocracking.

Roofing product manufacturers have introduced less expensive roofingproducts that simulate wood shakes and slate roofing. For example, someasphalt shingles have been developed that resemble wood shake or slateshingles. These asphalt products, however, typically do not have thestructural rigidity of slate or wood. Metal and plastic shingles thatsimulate wood shake and slate shingles also have been developed. Theseproducts, however, are subject to denting and breakage.

Roofing product manufacturers have also developed composite roofingproducts that resemble more traditional roofing products, including woodshakes and slates. Manufacturing these composite roofing products, whichare typically composed of at least a polymer and a filler component, hastraditionally involved the use of extrusion, pressing, and/or moldingtechniques. An example of a process involving extrusion of roofingproducts composed primarily of asphalt appears in U.S. Pat. No.5,690,876 to Gallo, Jr. Examples of molding processes used in makingcomposite roofing products include those in U.S. Pat. Nos. 6,025,052 toMaurer et al.; 6,112,492 to Wells et al.; and 5,635,124 to Abrams et al.Finally, use of both extrusion and molding is disclosed in U.S. Pat. No.6,290,885 to Nakai et al.

Although some of these patents promote economics of scale in aspects oftheir manufacturing, the references do not disclose a manufacturingsolution that takes advantage of economics of scale and that may beautomated from virtually beginning to end.

SUMMARY OF THE INVENTION

In order to overcome the stated problems and limitations there isprovided a method for creating shingles through the use of at least apartially automated system. In one embodiment, the method of the presentinvention includes an automated procedure having the steps of creating amixture having a filler and a polymer, forming a sheet from the mixture,cooling the sheet, embossing the sheet, foaming multiple roofingproducts from the sheet, and associating at least some of the roofingproducts with one another. In another embodiment, the present inventionincludes a method of making shingles that comprises the steps ofcreating composite shingles using at least one mold cavity, using arobot to transfer some of the shingles from some of the mold cavities toa conveying system, and stacking together at least two of the shingleswherein the shingles have different colors or different surfaceconfigurations.

Additional objects, advantages and novel features of the presentinvention will be set forth in part in the description which follows andthe attached figures and will in part become apparent in practice.

BRIEF DESCRIPTION OF THE DRAWING

The present invention is described in detail below with reference to theattached drawing Figures, wherein:

FIG. 1 is a schematic representation of a sheet line layout that may beused in accordance with the present invention;

FIG. 2A is a schematic representation showing one embodiment of afeeder/material handler, and extruder combination that may be used tocarry out the present invention;

FIG. 2B is a schematic representation showing one embodiment ofequipment that may be used to perfatin the bundling step of the presentinvention;

FIG. 3 is a flowchart illustrating one embodiment of the process of thepresent invention;

FIG. 4 is a flowchart illustrating one embodiment of the process ofbundling the shingles;

FIG. 5 is a flowchart illustrating the process in FIG. 3 with theaddition of a recycling step;

FIG. 6 is a schematic representation of one embodiment of an injectionmolding layout process of the present invention;

FIG. 7 is a schematic representation of the injection molding layoutprocess continued from FIG. 6;

FIG. 8 is a flowchart illustrating one embodiment of the injectionmolding process;

FIG. 9A-9C are flowcharts similar to FIG. 8 with the additional steps ofpalleting, wrapping, and strapping the stack; and

FIG. 10 is a flowchart similar to FIG. 8 with an additional step ofrecycling the scrap.

DETAILED DESCRIPTION OF THE INVENTION

Those skilled in the art will appreciate that in this detaileddescription certain well known components and assembly techniques havebeen omitted so that the present methods are not obscured in unnecessarydetail. Dimensions provided in English units may be translated tocorresponding metric units by rounding to the nearest millimeter.

Sheet Line Method

One or more of the present methods may be used in accordance with thesheet line method shown in FIG. 1. One such method is designated withreference numeral 200, the steps of which are illustrated in FIG. 3. Instep 210, a mixture is created from starting materials that include atleast a polymer and a filler. Additional additives, including acolorant, a fire retardant and/or an ultraviolet light protector, mayalso be included in the starting materials.

As shown in FIG. 1, step 210 may be carried out by using an extruder 10,which may include (e.g., be connected to) a mixer. To create themixture, the starting materials are fed into extruder 10. When extruder10 includes a mixer, the starting materials are fed by feeders and/ormaterial handlers into a hopper of the mixer. For example, as best seenin FIG. 2, three feeders/material handlers 20 may be used to feedstarting material into a hopper 12 of a mixer connected to extruder 10.Although not shown, the feeders/material handlers may be coupled witheach other so that the components of the eventual mixture (e.g., atleast a polymer and a filler) are mixed prior to being dumped into thehopper of the mixer (or hopper of the extruder if the extruder lacks aseparate mixer) where additional mixing occurs. The mixing by one ormore of the feeders and/or material handlers is within the scope of step210.

Examples of starting materials for the mixture include a polymer such aspolyethylene and a filler such as limestone. Specifically, thepolyethylene may be high- or low-density polyethylene, and may be virginor recycled. The limestone used in the mixture may be crushed orotherwise broken into small pieces. As indicated, a colorant or dye mayalso be used as a starting material, as may other materials such asUV-protectors and fire retardants. The starting materials may be fed atambient temperature into extruder 10 or, in the alternative, thestarting materials may be fed at ambient temperature intofeeders/material handlers 20. If used, feeders/material handlers 20 worktogether to mix the starting material and to heat them to some extent(but not necessarily to a molten state) prior to transferring thematerial into extruder 10 or, in some cases, hopper 12 of a mixerconnected to extruder 10.

Suitable extruders for use in the present invention include, but are notlimited to, hot-feed (i.e., the starting materials enter the extruder ina state heated above ambient temperature), cold-feed (i.e., the startingmaterials enter the extruder at ambient temperature), or screw-typeextruders, such as single-screw or multiple-screw extruders. When nomixer is attached to extruder 10 to carry out step 210, it will beunderstood that an extruder with a screw designed to mix the startingmaterials to create the mixture may be used. Alternatively, where amixer is used in creating the mixture, the extruder may include a feedscrew that is designed to pump the mixture and not contribute to thecreation of the mixture.

One example of a suitable extruder for use with the present methods isthe CP2500 manufactured by the Farrel Corporation in Ansonia,Connecticut and described, at least in part, in the CP2500V Series II™Instruction Manual from Farrel Corporation. The CP2500 includes acontinuous mixer, where the starting materials are introduced, and anextruder, where the mixture is released. More specifically, the startingmaterial is compounded within the mixing chamber barrel of the CP2500where it is heated until the polymer reaches a molten state. The mixturereceives heat from both the externally-heated mixing chamber barrel andthe friction between the rotors of the mixer, the mixture itself, andthe inside of the barrel. As a result of the heating, the polymer willencapsulate some or all of the filler. The temperature of the mixture atthis point may be between about 325 to 600 degrees Fahrenheit.

Continuing with this example of creating a mixture at step 210, theheated barrel of the mixer may be controlled to adjust the temperaturelimits of the mixture. A maximum temperature may be set, and if thetemperature of the mixture exceeds that maximum temperature, theexternal heater will turn off. A minimum temperature may also be set,and if the temperature of the mixture falls below or starts off at orbelow that minimum temperature, the external heater of the mixingchamber barrel will turn on. It should be understood that the externalheater of the barrel may operate continuously although it may be trippedoff under the appropriate circumstances.

After creating the mixture in step 210, a sheet is formed in step 220.As shown in FIG. 3, a sheet may be formed by extruding the mixturethrough a die such as a sheet die 14. It will be understood that die 14may be in the form of a sheet die or any other similar structure ordevice. Die 14 is shown generally as a point on the end of extruder 10in FIGS. 1 and 2. In carrying out step 220, extruder 10 forces themixture through die 14 thereby forming a sheet that then begins totravel along a conveyor, such as conveyor belt 30. The temperature ofthe sheet after exiting die 14 may be between about 225 to 500 degreesFahrenheit.

When using the CP2500, the mixture is fed from the mixer to the extruderthrough an enclosed connecting chute. The CP2500 is equipped with apneumatically-operated pusher assembly for the extruder hopper thatallows the mixture to be crammer-fed into the extruder barrel. Theextruder of the CP2500 has a feedscrew that is designed to pump onlyand, therefore, the extrusion of the mixture will raise its temperatureminimally, if at all. It should be understood, however, that both thehopper and the barrel of the extruder are externally heated, so themixture may be kept in a molten state to facilitate formation of thesheet. Thus, in carrying out step 220, a sheet may be formed by forcingthe mixture through die 14 using the feedscrew of the extruder on theCP2500.

One example of a die 14 that may be used for carrying out step 220 is a28-inch Masterslide HD sheet die available from Battenfeld GloucesterEngineering Company, Inc. of Gloucester, Massachusetts. Preferably, die14 will be dimensioned to create a sheet that is approximately ¼ inchthick by 26 inches wide. Of course, other sheets of other desireddimensions may be created using different dies.

Step 230 includes smoothing the sheet, which may be accomplished bypassing the sheet through a pair of calendar rolls (sometimes referredto as a “calendar stack” in the art). As best seen in FIGS. 1 and 3, thesheet formed in step 220 may be conveyed along conveyor belt 30 tocalendar rolls 40, which are oriented one above the other.Alternatively, extruder 10 and die 14 may be positioned sufficientlyclose to calendar rolls 40 so that conveyor belt 30 is unnecessary.Conveyor belt 30 may be driven automatically or manually. In addition,to smoothing the sheet, calendar rolls 40 also may reduce the thicknessof the sheet by adjusting the nip setting (i.e., the distance betweenthe surfaces of the rolls). Calendar rolls 40 may either be stationaryand unconnected to conveyor belt 30 or be coupled by a movable stationto conveyor belt 30 so that the position of calendar rolls 40 may varyalong a continuous section of conveyor belt 30. After smoothing thesheet by passing it through calendar rolls 40, the temperature of thesheet may be between about 175 to 300 degrees Fahrenheit.

One example of a pair of calendar rolls suitable for use in the presentinvention is a 24-inch by 32-inch Model 2000 ST Hydraulic 2-Roll stackavailable from Battenfeld Gloucester Engineering Company, Inc. anddescribed, at least in part, in the Model 2000 Roll Stack GeneralInformation Guide and Vertical Roll Stack Operation and MaintenanceManual from Battenfeld Gloucester Engineering Company, Inc. Thisparticular roll is equipped with electrically-powered heating andcooling elements that allow the calendar rolls to be heated or cooled asdesired.

Continuing with method 200, after the sheet is smoothed, the sheet willproceed along conveyor belt 30 to an embossing station 60, which isdesigned to impart features to the sheet for the purpose of ultimatelycreating a roofing product shaped like or having the appearance of woodshakes, slate or tile. As the sheet moves toward embossing station 60along conveyor belt 30, step 240 of cooling all or a portion of thesheet occurs.

Step 240 may occur at cooling station 50. Cooling station 50 is operableto reduce the temperature of at least a portion of the sheet. There area number of devices that may operate as cooling station 50. For example,cooling station 50 may be a Model No. RM-30-10-70 cooling conveyor (alsodescribed as a cooling conveyor section) manufactured by EMI Corporationlocated in Jackson Center, Ohio and described, at least in part, in theEMI Plastics Equipment Conveyor Operation & Maintenance Manual.Alternatively, cooling station 50 may be a device such as a misterhaving one or more nozzles. When a mister is used, water mist is sprayedout of the one or more nozzles onto the sheet passing below. A drip panis positioned beneath the relevant portion of conveyor belt 30 to catchthe water as it runs off the sheet and the conveyor belt. The water fromthe drip pan or pans is then channeled automatically to one or morecoolers, where it is recycled to the nozzles. In yet another embodiment,cooling station 50 may comprise the combination of a conveyor, such as acooling conveyor, and a device configured to reduce the temperature of aportion of the sheet, such as a mister. After step 240, the temperatureof the sheet may be between about 150 to 250 degrees Fahrenheit.

At step 250, the sheet is embossed. As shown in FIG. 1, the sheettravels along conveyor belt 30 to embossing station 60, which maycomprise one or two rolls. Like calendar rolls 40, embossing station 60may be separate from and in a fixed position along conveyor belt 30 ormay be coupled to the conveyor such that the position of embossingstation 60 may be varied along a continuous section of conveyor belt 30.Embossing station 60 may comprise two rolls where at least one of therolls is used to emboss a portion of the sheet located on conveyor belt30. For example, when two rolls are used as shown in FIG. 1, the oneroll in the embossing station may have a textured surface so that thesheet receives features that simulate either wood, slate, or shake. Thesecond roll may be smooth or textured. As another example, the secondroll may have a surface that is smooth except for being configured tomark information on the sheet such as the date, company name, style ofshingle, or additional types of information. One or more of the rollslocated at embossing station 60 may be equipped withelectrically-powered heating and cooling elements so that the rolls maybe heated or cooled as desired. An embossing machine suitable for use asembossing station 60 is a Two Roll Vertical Closed Frame Embossermanufactured by BF Perkins located in Rochester, N.Y. and described inthe Instruction Manual for BF Perkins 12″ Dia.×28″ Face Two RollVertical Closed Frame Calendar. After embossing the sheet at step 250,the temperature may be between about 130 to 220 degrees Fahrenheit.

After step 250 of embossing the sheet, the sheet may be cooled again atstep 260. Cooling station 52 may be used to carry out this cooling andmay be configured in the same way as cooling station 50 described above.Specifically, cooling station 52 may comprise a device configured toreduce the temperature of the sheet such as a cooling conveyor orcooling conveyor section, a mister, or both. Alternatively, coolingstation 52 may comprise two devices configured to reduce the temperatureof the sheet, the two devices being place side-by-side. The same type ofmister described above may be used for each of these two devices in thisexample. In yet another embodiment, cooling station 52 may comprise twocooling conveyor sections. The same type of cooling conveyor describedabove may be used in this example in two 10-foot sections. As stillanother embodiment, cooling station 52 may comprise two coolingconveyors, each coupled to a device configured to reduce the temperatureof the sheet, such as a mister. Again, the type of mister and the typeof cooling conveyor described above may be used for this version ofcooling station 52. After cooling the sheet at step 260, the temperaturemay be between about 100 to 200 degrees Fahrenheit.

To the extent that water is used with cooling stations 50, 52 and 54(station 54 will be discussed below), the cooling stations may becoupled to each other in a way that allows the same water to be used andthen recycled by each station. For example, each mister may be coupledtogether such that the water collected in the drip pan or pans beneatheach is directed to a common cooler or coolers that include a heatexchanger. Further, such water use may be closed (i.e., new water is notadded after a certain point) or open (new water is added at regularintervals).

Also, it should be understood that one or more cooling conveyors that donot use water may be used as a cooling station 50, 52 and 56. Thecooling conveyor may, for example, allow the sheet to cool in theambient air.

After cooling the sheet in step 260, step 270 involves forming multipleroofing products from the sheet. For example, a cutter 70 may be used tocut the sheet. Cutter 70 may be configured as a roll with the outersurface of the roll containing a series of knives arranged to cutmultiple roofing products across either the length or the width of thesheet. An example of a cutter 70 that may be used in forming multipleroofing products is the Compact Model Web-Fed Soft Anvil Rotary DieCutter, available from CORFINE in Dayton, Ohio. Such a cutter uses acutting roll and a die. After step 270, the temperature of the roofingproducts may be between about 80 to 180 degrees Fahrenheit.

Next, at least some of the roofing products, and possibly all of them,are cooled at step 280. Such cooling may take place, for example, usingcooling station 54. Cooling station 54 may comprise one or more coolingconveyors, such as, for example, four ten-foot sections of coolingconveyors. The EMI cooling conveyors described above may be used toaccomplish this task. Alternatively, as with the other cooling stations,a device configured to reduce the temperature of the sheet—such as amister—may be used with regular conveyors. One or more of such devicesmay be used in this regard, and the misters described above may be usedas the device. After step 280, the cooled shingle may be between about70 to 175 degrees Fahrenheit.

The position of the finished shingles is shown as numeral 80 in FIG. 1.

After cooling at least some of the shingles according to step 280, step290 involves bundling at least some of the shingles. Step 290 may occurat station 120 as shown in FIG. 1. As best shown in FIG. 4, oneembodiment of bundling step 290 involves stacking some of the shinglesto form a stack at step 292, placing the stack on a pallet at step 294and wrapping the stack at step 296. The stacking, placing and wrappingsteps may be accomplished using an automated procedure. This means thatthe procedure is designed to accomplish the stacking, placing, andwrapping without human intervention, although human intervention may beused at times to address malfunctions or to manually override theautomation.

FIG. 2B illustrates a layout of the equipment that may be used to carryout one embodiment of steps 292, 294 and 296. In particular, conveyor 30may be linked to a variable speed conveyor 31 that is available from VanPak Corporation located in Maryland Heights, Missouri. Variable speedconveyor 31 carries the shingles to a robot 121 that is configured toplace the shingles into stacks 122. Robot 121, therefore, may beconfigured to carry out step 292. The speed of variable speed conveyor31 may be set with respect to the speed of conveyor 30 to create spacebetween the parts as they are delivered to robot 121. An example ofrobot 121 is the Industrial Robot IRB140 available from ABB of Vasteras,Sweden.

Robot 121 is configured to place stacks 122 in the loading queue of astrapper 154. Strapper 154 may be configured to place one or more strapsaround stack 122 to ensure that the shingles are aligned with eachother. For example, strapper 154 may be configured to strap stack 122across the width of the shingles. Strapped stack 122 may then be ejectedfrom strapper 154 onto a conveyor 32 equipped with a turning cross(represented by the letter “X”). A conveyor such as conveyor 32 is alsoavailable from the Van Pak Corporation. Conveyor 32 is operable torotate a strapped stack 90-degrees and return the rotated stack tostrapper 154 to be strapped again across the length of the shingles. Asuitable strapper for use as strapper 154 is the Model TR3C 700/550In-Line Strapping Machine available from EAM-Mosca Corporation locatedin West Hazleton, Pennsylvania. Such a strapping machine may be alteredfrom its stock condition to include guides and stops that will cause thestacks to be in the proper location for the strapping to take place.

Alternatively, conveyor 32 may be configured to advance the strappedstack 122 to a palletizer 160 which is operable to place the stack on apallet and, therefore, may be used to accomplish step 294 of placing astack 122 on a pallet. An example of a suitable palletizer for use aspalletizer 160 is the Series 2000 Gantry Palletizer available from theVan Pak Corporation. Palletizer 160 may be equipped with a gantry-stylerobot to pick up an incoming stack 122 with vacuum cups and deliver itto a pallet at the loading station 158. The robot may be configured toplace stack 122 on a pallet in multiple orientations to best ensure thatthe pallet is mechanically stable. For example, the robot may beconfigured to rotate a stack placed on top of another bundle by 90degrees. Palletizer 160 also may be equipped with one or more loadingstations 158 for stacking strapped stacks 122 on one or more pallets.Finally, queuing stations 156 may be provided as part of conveyors 32 oras part of palletizer 160. Queuing stations 156 are configured to queuestrapped stacks 122 prior to the palletizing of the stacks.

Once a pallet has been loaded with one or more stacks 122, the loadedpallet may be ejected from the loading station by a powered chainconveyor 162 and delivered by a shuttle conveyor and dual conveyorshuttle car system 165. Suitable chain conveyors and shuttle conveyorand dual conveyor shuttle car systems are available from the Van PakCorporation. Shuttle conveyor and dual conveyor shuttle car system 165may be configured to accept loaded pallets from palletizer 160 anddeliver them to a wrapping station 167. The process for transferring theloaded pallets from palletizer 160 to wrapping station 167 involves thedual shuttle car shifting on its shuttle conveyor to align with theloading station that is ready to deliver a loaded pallet, accepting aloaded pallet, and then shifting along its shuttle conveyor to alignwith power chain conveyor 38, which communicates with wrapping station167. Empty pallets may be loaded into one or more pallet dispensers 169,which can then transfer the empty pallets back to one or more loadingstations 158 for use by palletizer 160.

Wrapping step 296 of the present sheet line methods may be carried outat, for example, wrapping station 167 which includes a stretch wrapper171, such as the model FA-66 Orion Automatic Stretch Wrapping Machineavailable from Orion Packaging Systems, Inc. in Collierville, Tennessee.Wrapping film may be fed to stretch wrapper 171 from a supply wheel 173.Loaded pallets are then wrapped (e.g., stretch wrapped) using stretchwrapper 171. The wrapped pallet may then be ejected onto a powered chainconveyor (available from Van Pak Corporation) and queued. A lift truck175 may then take the wrapped pallet to storage or to another location.

As shown in FIG. 5, in an alternative method 300, step 298 includesrecycling scrap from the cutting of step 270. This recycling step may becarried out by collecting scrap from the sheet and routing the scrapback to extruder 10 along another conveyor (not shown in FIG. 1). Thescrap may then be placed back into extruder 10 and reused in method 300.This recycling may start at one or more locations along conveyor belt 30(see also FIG. 5). For example, FIG. 1 shows that scrap may be taken atpoints 90 and 100, at cutter 70 beyond cooling station 54, and routedback to extruder 10 as indicated by arrow 110. One way in which thisrecycling may be achieved at point 90 involves scrap material fallingaway from conveyor 30 to another, underlying conveyor after the sheet iscut. The underlying conveyor (not shown) will then route the scrap to agrinder (also not shown) such as a Rapid Granulator Model R-36 availablefrom Rapid Granulator, Inc. in Rockford, Ill. The grinder then grindsthe scrap material to a desired state. Next, the ground scrap may beconveyed to a storage bin for use at an appropriate future time. At thedesired time, which may be preset as part of the automated process, theground material may be transported from the bin to a feeder, such asfeeder/material handler 20 shown in FIG. 2A, for re-introduction intomixer 10. This transportation may take place in any suitable way,including, for example, by a vacuum connecting to the bin to the feeder.

Some or all of the steps of methods 200 and 300 may be performed usingan automated procedure. This means that the steps performed in thismanner are designed to be accomplished without human intervention,although human intervention may be used at times to address malfunctionsor to manually override the automation. Step 210 of creating a mixturehaving a filler and a polymer will, when using an automated procedure,be understood not to exclude steps that involve human intervention toplace starting materials in the appropriate locations from which theremainder of the process can be accomplished.

Injection Molding Methods

One or more of the present methods also may be used in accordance withthe injection molding systems shown in FIGS. 6 and 7. One such method isillustrated in FIG. 8 and generally referred to by the numeral 400. Inparticular, step 410 of method 400 is creating multiple shingles usingmold cavities. (The phrase “mold cavities” does not include what areknown in the art as dies.)

It should be understood that carrying out step 410 may be achieved in avariety of ways. One way to carry out step 410 involves use of thepelletizer schematically shown in FIG. 6. Extruder 10, which may be theCP2500 discussed above, may be used to create a mixture having a polymerand a filler such as the polymer and filler discussed above. As bestseen in FIG. 6, the mixture may then be pushed through pelletizer 310and cut using pelletizer 310 to form one or more pellets 320. Theprocess of creating pellets may be referred to as pelletizing themixture. A suitable pelletizer is an Underwater Pelletizer Model MAP-7from Gala Industries, Inc. located in Eagle Rock, Virginia. Thispelletizer may be attached to the end of extruder 10.

Preferably, the size of pellets 320 created using pelletizer 310 will bebetween about 0.110 and 0.150 inches in diameter. It will be understoodthat other diameters may be more suitable for other applications. Thetemperatures of the mixture going into the pelletizer may be betweenabout 350 to 400 degrees Fahrenheit. The temperature of the resultingpellets may be between about 100 to 150 degrees Fahrenheit.

As shown in FIG. 6, pellets 320 may then be dried using a dryer 325.Dryer 325 is useful where pellets 320 have been created using anunderwater pelletizer, such as the Gala pelletizer discussed above.However, if pellets 320 are not created using a liquid then dryer 325may not be necessary. When the pellets are finished drying, theirtemperature may be between about 80 to 150 degrees Fahrenheit. Asuitable dryer for use as dryer 325 is the Centrifugal Pellet DryerModel 16.3 BF ECLN, available from Gala Industries, Inc. After drying,pellets 320 may be routed to storage, as indicated by arrow 335.

Continuing with step 410, pellets 320 may be taken from storage, orrouted directly from dryer 325, and placed in one or more injectionmolders 330 as best seen in FIG. 7. Each injection molder 330 that isused may include a mixing barrel designed to mix the pellets and raisethe temperature of the pellet material (e.g., the mixture referencedabove) to a molten state, or between about 350 to 500 degreesFahrenheit. Each injection molder 330 that is used may include asingle-screw with a barrel that is externally heated to raise thetemperature of the pellet material. The pellets may be heated by theexternal heater of the barrel, and by the friction created between thescrew rotor, the pellet material, and the inside of the screw barrel. Ifa colorant is used, it may be added during the mixing of the pelletmaterial in a given injection molder 330.

FIG. 7 shows two injection molders 330 being used in the presentinvention. It will be understood, however, that as few as one injectionmolder may be utilized with the present methods, provided the injectionmolder includes a mold having two or more cavities. Further, as manyinjection molders 330 as desired may also be used, such as 15, forexample. Colorant may be added using a volumetric or gravimetric colorfeeder, such as the Thoresen McCosh WSB-260T available from ThoresonMcCosh in Troy, Michigan, that is coupled to one or more of theinjection molders 330. An injection molder suitable for use as one ofthese injection molders is the Van Dorn HT Model 500 injection moldermanufactured by Van Dorn Demag Corporation in Strongsville, Ohio.

Continuing with a description of how one injection molder 330operates—with the understanding that multiple injection molders may beused and that this description applies to as many as are used—frominjection molder 330, the mixture will be heated and injected into themold cavities 340. If only one injection molder 330 is used, multiplemold cavities 340 (e.g., two, three or more) should be used consistentwith the present methods. If multiple injection molders are used, eachinjection molder may have as few as one mold cavity 340, although two,three, or more mold cavities 340 may be used in each of the multipleinjection molders. Throughout this disclosure, however, a single block340 in each injection molder 330 represents one or more mold cavities,and this description will sometimes discuss the operation and use of asingle mold cavity 340 in explaining the present methods.

Mold cavity 340 will be cast or machined to have one or more surfacesconfigured to resemble wood shake, slate or tile shingles. Mold cavity340 may be made in two, three, or more pieces, and may be made of metalsuch as P20. Mold cavity 340 may be machined to have a surface orsurfaces formed using digitized modeling. The digitized model may be ofthe target shingle, such as shake, slate or tile, and each mold cavity340 may be configured to produce a separate product.

As part of step 410, the shingles created may be cooled by running wateror another suitable coolant through the one or more mold cavities 340.This type of cooling may serve to restrict the flow of the mixture intothe mold cavity. The amount of mixture to be placed in each mold cavitymay be determined by weight or volume, which is determined substantiallyby the desired size and shape of the shingles being formed.

After step 410, and after the shingles in mold cavities 340 have beensufficiently cooled to a temperature of between about 70 to 170 degreesFahrenheit, step 420 may occur. More specifically, step 420 involvestransferring some of the shingles from some of the mold cavities to aconveyor or multiple conveyors, such as conveyor belts 30 in FIG. 7,using one or more robots 360. A suitable robot for use as robot 360 isthe Sailor model RZ-300N2S-M3L available from Sailor USA located inKennesaw, Georgia. Each robot 360 may be positioned about the clamp (notshown) of an injection molder 330. Once the molding process is completeand the product is ready to be removed from the mold cavities, the clampof injection molder 330 will open and robot 360 will remove the finishedpart or parts from the mold cavity or cavities. Robot 360 may then movealong a beam 361 that allows it to translate between injection molder330 and conveyor 30. Robot 360 will place the part on conveyor 30, whereit will travel to a packaging area. As shown in FIG. 7, beams 361 may beconfigured to allow the robot of each injection molder to access eitherconveyor 30. Examples of suitable conveyor belts for use as conveyor 30in FIG. 7 are TEC's Classic Steel Horizontal Conveyors available fromTEC Engineering, located in Oxford, Massachusetts.

Recycling of scrap material at step 460 of method 600 shown in FIG. 10may also be started at this point of the process. One way of recyclingscrap involves the use of a conveyor, such as conveyor 37, which may bea TEC Classic Steel Horizontal Conveyor available from TEC Engineering.Conveyor 37 may be positioned along the path accessible on beam 361 byrobot 360. As robot 360 travels along its beam, it may stop at conveyor37, break off any runner or other scrap material attached to thefinished product it is transporting, and place that scrap material ontoconveyor 37. Conveyor 37 may then transport the scrap material to agrinder 370 such as a Rapid Granulator Model R-36, available from RapidGranulator, Inc. located in Rockford, Ill. After the scrap material isground using grinder 370, it may be transported to a storage bin 372,which may be preset as part of an automated process. Blender 374 maythen re-mix the ground scrap with any other desired materials anddeposit the blended material back into the feed throats of one or moreof the injection molders 330.

Although not shown with a cooling station or stations such as thosedescribed above, conveyor belts 30 may be equipped with such coolingstations in order to cool the roofing products placed on conveyor belts30 by robots 360.

Each injection molder 330 may be configured to produce finished shinglesof a certain color. The mold cavities or cavities 340 in each injectionmolder 330 will produce the same colored shingles as a result. Differentinjection molders may be configured to produce shingles with differentcolors.

After step 420, at least two roofing products or shingles with eitherdifferent colors or different surface configurations will be positionedbeside each other on a conveyor belt 30. By different colors it will beunderstood that two colors have different hues, different values, ordifferent chroma on the Munsell scale. The use of “different” in thephrases “different colors” and “different surface configurations” doesnot include those differences due to chance. The differences to which werefer to are those that are purposefully created.

Such different products will then travel along conveyor belts 30 tostation 190, where step 430 may be carried out. Step 430 involvesstacking together at least two of the shingles that have differentcolors or different surface configurations. Two such stacks arerepresented in FIG. 7 by the numeral 376. Of course, more than twoshingles may be included in such a stack, however, at least two of themmust have different colors or different surface configurations.

Another method of the present invention is illustrated in FIG. 9A and islabeled as numeral 500. Method 500 involves additional use of station190. In addition to steps 410, 420 and 430 as described above, method500 includes taking the stack created in step 430 and placing it on apallet in step 440. Further, method 510, shown in FIG. 9B includes steps410-440 of method 500, and the additional step 450 of wrapping thestack. Method 520 shown in FIG. 9C includes steps 410-450 of method 510and the additional step 445 of placing a strap around the stack, whichas described previously may take place prior to the wrapping of thestack. As in the case of steps 292, 294 and 296 discussed above, thestacking, placing, strapping and wrapping steps of methods 500, 510 and520 may be accomplished using an automated procedure.

Returning to FIG. 7, one example of the equipment that may be used forstation 190 to accomplish one or more of steps 430, 440, 445 and 450 ofFIGS. 8-9C is shown. As best seen in FIG. 7, each conveyor 30 may belinked to a variable speed conveyor 31 that is available from Van PakCorporation, Maryland Heights, Missouri. Each variable speed conveyor 31carries the shingles to a stacker 150. The speed of variable speedconveyor 31 may be set with respect to the speed of conveyor 30 so as toposition the parts at a distance apart from one another as they aredelivered to the stacker 150. An example of a suitable stacker is a VanPak Vertical Stacker (i.e., a Lowerator) from the Van Pak Corporation.Stacker 150 stacks multiple finished shingles (e.g., up to 15). Stacker150 may be configured to carry out step 430 of stacking at least tworoofing products with different colors or surface configurationstogether to create stack 376. The number of stackers 150 used willdepend on the number of incoming conveyors 30—generally, there is aone-to-one correspondence.

As shown in FIG. 7, each stacker 150 may be provided with a queuingstation 151 into which stacks 376 are inserted. Stacker 150 may thenindex downwardly and deliver a given stack 376 onto another conveyor 152that transports the stack to strapper 154. Suitable conveyors forconveyor 152 are available from the Van Pak Corporation.

Strapper 154 may be configured to carry out step 445 by placing one ormore straps around stack 376. Using straps helps ensure that the roofingproducts become and remain aligned with each other. For example,strapper 154 may be configured to strap stack 376 across the width ofthe roofing products. The strapped stack may then be ejected fromstrapper 154 onto a conveyor 32 equipped with a turning crossrepresented by the letter “X” (such a conveyor is also available fromthe Van Pak Corporation). Conveyor 32 may be configured to rotate astrapped stack 90 degrees and return the rotated stack to strapper 154to be strapped again across the length of the shingles. A suitablestrapper for use as strapper 154 is an EAM Mosca Model TR3C 700/550In-Line Strapping Machine available from the EAM-Mosca Corporation, WestHazelton, Pennsylvania. Such a strapping machine may be altered from itsstock condition to include guides and stops configured so as to positionthe stacks in the proper location for the strapping to take place.

Alternatively, conveyor 32 may be configured to advance the strappedstack 376 to a palletizer 160. Queuing stations 156 may be provided aspart of conveyors 32 or as part of palletizer 160. These queuingstations are configured to queue strapped stacks 376 to the palletizingof the stacks.

An example of a suitable palletizer for use as palletizer 160 is theSeries 200 Gantry Palletizer available from the Van Pak Corporation.

Palletizer 160 may be equipped with one or more loading stations 158 forstacking strapped stacks 376 on one or more pallets, which may be madeof wood. This process may be used to accomplish step 440 of placing astack on a pallet. Palletizer 160 may be equipped with a gantry-stylerobot to pick up an incoming stack 376 with vacuum cups and deliver itto a pallet on one of the loading stations 158. The robot may beconfigured to place stack 376 on a pallet in multiple orientations tobest ensure that the loaded pallet is mechanically stable. For example,the robot may be configured to rotate a stack placed on top of anotherbundle by 90 degrees.

Once a pallet has been loaded with strapped stacks 376, the loadedpallet may be ejected from the loading station by a powered chainconveyor 162 and delivered by a shuttle conveyor and dual conveyorshuttle car system 165. Shuttle conveyor and dual conveyor shuttle carsystem 165 may be configured to accept loaded pallets from palletizer160 and deliver them to wrapping station 167. The process for thistransfer of the loaded pallets from the palletizer to the wrappingstation involves the dual shuttle car shifting on its shuttle conveyorto align with the loading station that is ready to deliver a loadedpallet, accepting that loaded pallet, and then shifting along itsshuttle conveyor to align with power chain conveyor 38, whichcommunicates with wrapping station 167. Empty pallets may be loaded intoone or more pallet dispensers 169, which can then transfer the emptypallets back to one or more loading station s158 for use by palletizer160.

Wrapping step 450 of the present invention may be carried out at, forexample, wrapping station 167, which may include a stretch wrapper 171,such as the model FA-66 Orion Automatic Stretch Wrapping Machineavailable from Orion Packaging Systems, Inc. in Collierville, Tennessee.Wrapping film may be fed to stretch wrapper 171 from a supply wheel 173.Loaded pallets are then wrapped (e.g., stretch wrapped) using stretchwrapper 171. The wrapped pallet may then be ejected onto a powered chainconveyor (available from the Van Pak Corporation) and queued. A lifttruck 175 may then take the wrapped pallet to storage.

Some or all of the steps in methods 400, 500 and 600 may be performedusing an automated procedure. Step 410 of creating multiple shinglesusing mold cavities will, when using an automated procedure, beunderstood not to exclude steps that involve human intervention to placestarting materials in the appropriate locations from which the remainderof the creating step can occur.

The purpose of stacking together different roofing products or shingleswith different colors (not different colors within a given roofingproduct, but different colors of different roofing products) ordifferent surface configurations is to provide builders/roofers with theoption of easily applying such differently-colored or configured roofingproducts to a single roof. This is an attractive option where the colorsdiffer by chroma or value. The convenience of not needing to mix theroofing products from one pallet with the roofing products of anotherpallet on site in order to achieve a multi-colored roof or a roof thatincludes roofing products with different textures is one that is notenjoyed in the prior art.

It should be understood that the steps of the present methods need notbe carried out exactly as described above to fall within the scope ofthe claims and their equivalents. For example, the cooling of the sheetmay be carried out using pressurized air, as opposed to pressurizedwater or ambient air. Additionally, while particular embodiments of theinvention have been shown, it will be understood, of course, that theinvention is not limited thereto, since modifications may be made bythose skilled in the art, particularly in light of the foregoingteachings. Reasonable variation and modification are possible within thescope of the foregoing disclosure of the invention without departingfrom the spirit of the invention.

1. A method of manufacturing roofing products, said method comprisingthe following steps: (a) creating a mixture having at least a filler anda polymer; (h) forming a sheet from said mixture; (c) cooling the sheet;(d) embossing the sheet; (e) forming multiple roofing products from thesheet; and (f) associating at least some of the roofing products;wherein steps (a) through (f) are performed using an automatedprocedure.
 2. The method of claim 1 wherein said filler is limestone. 3.The method of claim 1 wherein said polymer is polyethylene.
 4. Themethod of claim 1 wherein said mixture also contains a colorant.
 5. Themethod of claim 1 wherein said mixture also contains a fire retardant.6. The method of claim 1 wherein said mixture also contains a UVprotector.
 7. The method of claim 1 wherein said creating step isperformed in an extruder machine.
 8. The method of claim 1 wherein saidstep of forming a sheet from said mixture is performed by extruding saidmixture from an extruder machine through a sheet die.
 9. The method ofclaim 1 wherein said cooling step is performed at least in part by acooling conveyor.
 10. The method of claim 1 wherein said cooling step isperformed at least in part by a mister.
 11. The method of claim 1wherein said step of forming multiple roofing products from the sheetincludes cutting said sheet to create said multiple roofing products.12. The method of claim 1 wherein said associating step comprises:stacking at least some of the roofing products thereby forming a stack;placing said stack on a pallet; and wrapping the stack.
 13. The methodof claim 12 wherein said associating step further includes placing astrap around said stack.
 14. The method of claim 1 wherein said step offorming multiple roofing products from the sheet creates a number ofroofing products and scrap and further comprising the step of: (g)recycling said scrap; wherein said steps (a) through (g) are performedin an automated procedure.
 15. A method for manufacturing roofingproducts, said method comprising the following steps: (a) creating amixture having a filler and a polymer; (b) forming a sheet by extrudingthe mixture through a die; (c) smoothing the sheet; (d) cooling thesheet using a first cooling station; (e) embossing the sheet; (f)cooling the sheet using a second cooling station; (g) forming multipleroofing products by cutting the sheet; (h) cooling at least some of theroofing products; and (i) bundling at least some of the roofingproducts.
 16. The method of claim 15 wherein said filler is limestone.17. The method of claim 15 wherein said polymer is polyethylene.
 18. Themethod of claim 15 wherein said mixture also contains a colorant. 19.The method of claim 15 wherein said mixture also contains a fireretardant.
 20. The method of claim 15 wherein said mixture also containsa UV protector.
 21. The method of claim 15 wherein said creating step isperformed in an extruder machine.
 22. The method of claim 15 whereinsaid first cooling station includes at least a cooling conveyor.
 23. Themethod of claim 15 wherein said first cooling station includes at leasta mister.
 24. The method of claim 15 wherein said second cooling stationincludes at least a cooling conveyor.
 25. The method of claim 15 whereinsaid second cooling station includes at least a mister.
 26. The methodof claim 15 wherein said bundling step comprises: stacking at least someof the roofing products to form a stack; placing the stack on a pallet;and wrapping the stack; wherein said steps are performed using anautomated procedure.
 27. The method of claim 26 wherein said bundlingstep further comprises placing a strap around the stack wherein saidstep is performed in an automated procedure.
 28. The method of claim 15wherein said step of forming multiple roofing products by cutting thesheet creates scrap and further comprising the step of: (j) recyclingsaid scrap.